Contact selecting finger for crossbar switches



July 19, 1949. E. A. WIBERG ET AL 2,476,739

CONTACT SELECTING FINGER FOR CROSS-BAR SWITCHES Filed Jan. 30, '1945 IN V EN TORS 5 frzW/l. M'berq .wardly when the magnet Patented July 19, 1949 CONTACT SELECTING FINGER FOR CROSSBAR SWITCHES Erik Axel Wiberg and Ernst Henrik Paulander,

Stockholm, Sweden, assignors to Telefonaktiebolaget L M company of Sweden Ericsson Stockholm, Sweden, a

Application January 30 1945, Serial No. 575,296 In Sweden March 13, 1944 2 Claims. 1

The present invention relates to a selecting finger for cross-bar switches. In a switch of this kind for indication of the spring group to be actuated by means of a horizontal operating bar, a number of Vertical selecting bars with, as a rule, rigidly mounted indication wires or contact selecting fingers are used. An object of the present invention is to provide a suitable construction for such a selecting finger which is not connected with the pertaining selecting bar. According to the invention and with the foregoin and other objects in view the indicating member consists of a rigid finger which lies entirely outside the pertaining selecting bar and which is arranged to be acted upon by said bar only when the corresponding operating bar has its inactive normal position.

The invention will hereinafter be more fully described with reference to accompanying drawing which shows an example of a contact selecting finger according to the invention and its use in a cross-bar switch. Figs. 1 and 2 are side views of the cross-bar switch and Fig. 3 is a plan view. The drawing illustrates only that part of the cross-bar switch which is required for a clear understanding of the invention. The switch may be of any known construction.

Each vertical selecting bar contained in the cross-bar switch is mounted to turn about pivot pins Ila and is provided with two armatures l3 and M which are arranged to be acted upon by the related magnets l5 and I6 respectively. This makes it possible for a selecting bar with arms I! mounted thereon to be turned in diiferent directions. According to the invention a special selecting finger 2| is provided for each arm l'l, said selecting finger being rigid. In that way each selecting bar has arms with pertaining selecting fingers up to a number corresponding to the number of operating bars contained in the switch. Each selecting finger 2| is pivotally supported at 23 in a bridle 22. The bridle 22 is rotatably mounted around the points 24 and may be acted upon by the operating bar I2 of the corresponding switch so as to be rocked upwardly and down- |8 acts upon the bar. The bar 2 is arranged to support a number of selecting fingers which corresponds to the number of selecting bars in the cross-bar switch. The selecting fingers are provided, adjacent the arm IT, with a claw which normally encircles the extremity of arm l1, Figs. 2 and 3. When the operating bar I2 is attracted and the bridle 22 is raised, the selecting fingers associated with the operating bar will be disengaged from the corresponding arm I1, Fig. 1. All the mechanism thus far described is mounted in known manner in the rack 20, 33 of the switch, as is also the case with the contact spring group 3| of the switch.

When, for example, the magnet I5 pertaining to selecting bar I I is magnetised it moves the bar I I from the normal position shown by continuous lines in Fig. 3 into the broken line position. The arm l1 thereby transmits that movement to selecting finger 2| which is turned about the pivot 23 into the broken line position. The foremost part of the selecting finger will be moved to a position between operating bar I2 and the righthand spring group 3|, Fig. 3, which is thus put under the control of the selecting finger. When thereafter the bar I2 is actuated, it raises its bridle 22 and the selecting finger 2| and the latter, by means of a strip 32 actuates all the movable contact springs in said right-hand contact spring group 3|. As previously mentioned, the selecting finger 2| is released from the selecting bar and the arm I! when the bridle is raised, and it now takes the position in relation to the arm I? as indicated in Fig. 1. Thus, the selecting bar II, when the operating bar is actuated, is completely released from the selecting finger 2|. When the magnet of the operating bar is demagnetised the bridle 22 returns to normal position 25 according to Fig. 2 and the selecting finger 2| may again be actuated by the arm IT.

We claim:

1. In a cross-bar switch, a movable vertical selecting bar, a movable horizontal operating bar,

two groups of contacts adjacent said selecting bar, a rigid selecting finger movable into operative positions with respect to either of said groups of contacts, a horizontal bridle supporting the selecting finger and operated by the horizontal operating bar from a normal unoperated position to an active position, means on said selecting bar effective when said bridle is in its unoperated position to move said selecting finger into either operative position whereby upon actuation of the operating bar the operatively positioned finger is caused to actuate the related group of contacts.

2. A cross-bar switch as claimed in claim 1 wherein said finger is disengaged from said selecting bar when the latter is in its active position.

ERIK AXEL WIBERG. ERNST HENRIK PAULANDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 5 Number Name Date 1,472,503 Taylor Oct. 30, 1923 1,530,998 Gofl Mar. 24, 1925 2,113,215 Magrath Apr. 5, 1938 2,120,413 Matthles June 14, 1938 

